出現此類錯誤原因大致為：

• 許可權問題
• 防火牆機制問題
• 共享配置檔案問題

搭建好nfs服務後，在client端進行掛載時，提示：

[root@web1 media]# mount -t nfs 192.168.0.124:/server/tools/repo /media/centos/
mount.nfs: access denied by server while mounting 192.168.0.124:/server/tools/repo

查看了一下client端是否被佔用了：

[root@web1 media]# mount -t nfs 192.168.0.124:/server/tools/repo /media/centos/
mount.nfs: access denied by server while mounting 192.168.0.124:/server/tools/repo
[root@web1 media]# mount
/dev/sda3 on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw,rootcontext="system_u:object_r:tmpfs_t:s0")
/dev/sda1 on /boot type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)

發現並沒有，然並卵。

接著就上server端檢視/etc/exports配置檔案：

[root@fenfa scripts]# cat /etc/exports
exporting 192.168.0.*:/server/tools/repo
exporting 192.168.0.*:/data

把192.168.0.24的/server/tools/repo共享給同一個網段的所有伺服器，把IP格式規範為192.168.0.0/24或192.168.0.0/255.255.255.0

[root@fenfa scripts]# vim /etc/exports 
[root@fenfa scripts]# exportfs -rv
exporting 192.168.0.0/24:/server/tools/repo
exporting 192.168.0.0/24:/data
[root@fenfa scripts]# showmount -e 127.0.0.1
Export list for 127.0.0.1:
/server/tools/repo 192.168.0.0/24
/data              192.168.0.0/24

我們再從client端上從新掛載：

[root@web1 media]# mount -t nfs 192.168.0.124:/server/tools/repo /media/centos/
[root@web1 media]# df -h
Filesystem                        Size  Used Avail Use% Mounted on
/dev/sda3                          19G  1.8G   16G  11% /
tmpfs                             491M     0  491M   0% /dev/shm
/dev/sda1                         194M   29M  155M  16% /boot
192.168.0.124:/server/tools/repo   19G  6.7G   11G  39% /media/centos

is ok!

如果解除安裝的時候提示： umount:/mnt:device is busy；解決方法：需要退出掛載目錄再進行解除安裝，或者是否NFS server宕機了

[root@web1 nginx-1.6.3]# umount -t nfs 192.168.0.124:/server/tools/rep /media/centos/
umount: 192.168.0.124:/server/tools/rep: not found
umount.nfs: /media/centos: device is busy
[root@web1 nginx-1.6.3]# umount -t nfs 192.168.0.124:/server/tools/rep /media/centos/
[root@web1 nginx-1.6.3]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda3        19G  1.9G   16G  11% /
tmpfs           491M     0  491M   0% /dev/shm
/dev/sda1       194M   29M  155M  16% /boot

需要強制解除安裝：mount –lf /mnt

此命令也可以：fuser –km /mnt不建議用

文章來自於作者：南清風